This invention relates generally to planar light circuits.
A planar light circuit is an optical circuit that uses integrated waveguides. These waveguides may be integrated into a substrate that, in some embodiments, may be an integrated circuit substrate. The planar light circuit may be formed using techniques that are known in forming integrated circuits.
Commonly it is desired to monitor the power in each channel in a planar light circuit. For example, in wavelength division multiplexed networks, a large number of channels, each with a different wavelength, may be multiplexed together. It is important to know the power of each channel since each channel may be ultimately separated, at its intended destination, from the multiplexed signal.
Existing circuits for monitoring power using planar light circuits are subject to cross talk between adjacently positioned detectors for different channels. Cross talk is any distortion of one channel caused by another channel.
Thus, there is a need for better ways to monitor power in planar light circuits.